The present invention relates generally to high intensity light emitting diodes (LEDs), and more particularly to the drivers and driver controllers used for illuminating the LEDs.
High intensity LEDs are commonly used in industrial settings for supplying illumination to high-speed camera equipment that takes pictures of products. In such settings, it is common for an automated camera to take pictures of the products being manufactured or assembled, often as the product passes by one or more particular points on an assembly line. Such pictures are often analyzed by a computer to determine if there are any defects in the product.
For example, in a bottling plant, a camera may be arranged along the assembly line where it takes a digital picture of each bottle as it passes by. A computer may then be used to analyze the picture taken to determine a number of different qualities of the bottled product, such as the following: whether a cap was properly attached to the bottle, whether the bottle was filled to an appropriate level, whether a label was applied to the bottle properly, whether the bottle is cracked, and various other qualities.
In order for the computer to analyze the photographs, it is often desirable that the illumination provided to the camera be nearly uniform for all of the pictures taken by the camera. This uniformity in lighting helps prevent the computer from misinterpreting the photographs due to changed lighting conditions. It may also be desirable to shut the lights off during the time intervals between photographs so as to conserve energy.
These types of demands have helped foster the use of high intensity LEDs for industrial photography situations. Because high-intensity LEDs are better able to produce the same amount of illumination over their lifetime, as compared to incandescent or fluorescent lighting, they are desirable for providing illumination in situations where constant levels of illumination are desired. Further, because high-intensity LEDs can be rapidly turned on and off and have favorable lifetimes relative to incandescent or fluorescent lighting, they are often used in high-speed photography situations.
Existing drivers for high-intensity LEDs, however, have suffered from several drawbacks. In some instances, the drivers powering the LEDs may not be able to turn the LEDs on in as fast as a time as would be desirable. In other instances, the current supplied to the LEDs by the driver does not stabilize for an undesirably long amount of time, thereby causing the illumination provided by the LEDs to fluctuate for the same amount of time. In some situations it is desirable to generate more illumination than the LEDs are rated to safely provide at continuous levels. Still further, in other situations it is not easy to set up and control the LED drivers in the particular ways demanded for a particular application.